1 files changed, 23 insertions, 0 deletions
diff --git a/lib/ansiblelint/rules/ComparisonToEmptyStringRule.py b/lib/ansiblelint/rules/ComparisonToEmptyStringRule.py
new file mode 100644
index 0000000..a43c4f7
--- /dev/null
+++ b/lib/ansiblelint/rules/ComparisonToEmptyStringRule.py
@@ -0,0 +1,23 @@
+# Copyright (c) 2016, Will Thames and contributors
+# Copyright (c) 2018, Ansible Project
+
+import re
+
+from ansiblelint.rules import AnsibleLintRule
+
+
+class ComparisonToEmptyStringRule(AnsibleLintRule):
+    id = '602'
+    shortdesc = "Don't compare to empty string"
+    description = (
+        'Use ``when: var|length > 0`` rather than ``when: var != ""`` (or '
+        'conversely ``when: var|length == 0`` rather than ``when: var == ""``)'
+    )
+    severity = 'HIGH'
+    tags = ['idiom']
+    version_added = 'v4.0.0'
+
+    empty_string_compare = re.compile("[=!]= ?(\"{2}|'{2})")
+
+    def match(self, file, line):
+        return self.empty_string_compare.search(line)